This invention generally relates to a flexure assembly that is useful for guiding reciprocating elements in a desired linear motion such as an armature within vibration test equipment.
A variety of vibration test devices are commercially available and commonly referred to as shakers or exciters or vibration generators. There are several basic components within most such devices including an armature suspended for movement relative to a stator. A coil is typically carried by the armature and located in an air gap between the armature and the stator. Permanent magnets or electromagnets are typically used to generate a D.C. magnetic field across the air gap. By feeding an alternating current through the coil, the armature is caused to reciprocate or vibrate along its longitudinal axis relative to the stator at the frequency of the applied alternating current.
Since the armature must move relative to the stator, it is typically mounted with a series of bearings and/or a plurality of peripheral suspension members. The bearings and suspension members serve the functions of centering the armature and allowing it to move along its longitudinal axis. Preferably, the armature is prevented from any lateral movement normal to the longitudinal axis along which the armature moves during vibration. A variety of bearings and suspension members have been proposed in the past, however, none have proven satisfactory for all conditions and circumstances. Typical problems with existing arrangements include distortion of the purity of the vibration motion caused by typical suspension members. Additionally, conventional arrangements typically do not adequately restrict off-axis movement and do not provide the degree of accuracy that is needed in many situations. Moreover, none of the prior systems adequately address all of these issues.
An additional problem presented by conventional bearings and suspension members is that they typically introduce noise during the vibration movement. Any additional noise is undesirable under circumstances where the purpose of the vibratory test is to determine squeaks and rattles within an item that is being tested. One example includes instrument panels that are included in passenger vehicles. During a testing operation, the ability to detect squeaks and rattles within an assembled instrument panel is compromised by extraneous noises that are created by the bearings or suspension members within the testing device.
Therefore, there is a need for an improved assembly that will allow for an armature within a vibration testing device to move along its longitudinal axis while also preventing any cross-axis motion and doing so with minimal noise. This invention addresses those needs and overcomes the shortcomings and drawbacks of the prior art described above.